Attachment for portable drills



Aug. 15, 1933.

H. H. EHLEN ATTACHMENT FOR PORTABLE DRILLS Filed March 9, 1931 INVENTOR B Ha /2w?! EHLEN ATTORN EY Patented Aug. 15, 1933 UNITED STATES PATENT OFFICE 1 Claim.

This invention relates generally to portable drills, and particularly to an attachment for increasing the usefulness thereof. The main object of this invention is to provide a simple means for increasing the force which can be brought to bear against the drill.

The second object is to increase the ease with which holes can be drilled and to increase the accuracy of the drilling by reducing the amount of physical effort required and permitting the operator to devote more attention to the manner in which the drill is held.

The third object is to provide an attachment for portable drills by means of which same may be easily converted into a post drill.

These, and other objects, will become more apparent from the specification following as illustrated in the accompanying drawing, in which:

Fig. 1 is a side elevation of the drill and attachment.

Fig. 2 is an end elevation.

Fig. 3 is a plan.

Fig. 4 is a horizontal section along the line 4-4 in Fig. 1.

Similar numbers of reference refer to similar parts throughout the views.

Referring in detail to the drawing, there is illustrated a common form of electric drill 10 from which the handle has been removed and a standard 11 substituted. Across the standard 11 is mounted a shaft 12 which is normal to the drill point 13. On the shaft 12' is mounted a hand lever. 14, on one end of which is formed a segment gear 15.

The frame of the attachment consists ofan elongated guide 16 to the upper portion of which is secured a rack 17 adapted to mesh with the gear 15. In order to hold the rack 17 and the gear 15 in their correct relationship there is provided a pair of arms 18 which are attached to the standard 11 by means of the screws 19. On the outer end of each arm 18 is mounted a roller 20. The pin 21 passes through both of the rollers 20. The rollers 20 ride on theribs 22 formed on the rear side of the guide 16.

Within the guide 16 is slidably mounted the slide 23 which is provided with a cut-away por tion 24 for the rack 17. At the lower end of the slide 24 is a bracket 25 which is secured to the drill 10 by means of the bolts 26. The upper end of the slide 23 is secured to or made integral with the standard 11. The end 27 of the guide 16 is bent outwardly (as illustrated) to permit the introduction of large pieces of work 28. The

end 27 is provided with an inturned portion 29 against which the work 28 is held during the drilling operation.

- The upper end 3i) of the guide 16 is provided with a hole 31 by means of which the entire device may be suspended from a nail 32 driven into a block 33 which is mounted on a post 34, or any other suitable support.

In the operation of this device as a portable drill the operator merely moves the lever 14 in 5 a direction away from the drill point 13 sufficiently far to admit the work 28. By reason of the increased leverage provided between the lever 14 and the gear 15 a very considerable force may be brought to bear against the drill point 13. If the hole being drilled is of such length, or the thickness of the worlcZS is sufficiently great to require same, the operator, by moving the lever 14, causes the gear 15 to move out of mesh with the rack 17 permitting the drill to be moved freely to the desired position, after which the gear 15 again brought into mesh with the rack 17, thereby enabling the user to select the best position for the drilling operation.

It can be seen from the foregoing that by the addition of a very small amount of weight the usefulness of the portable drill has been very much increased without detracting materially from its portability and all-around convenience.

In view of the fact that this device is so constructed that it is easily separable from the drill for use in locations which the attachment would otherwise render impossible, it may be found desirable to incorporate some form of handle on the standard 11 to render unnecessary the performing of any operation other than the sliding of the guide 16 away from the slide 23.

I claim:

In a device of the class described, a straight guiding frame having a rack at one end thereof in parallelism therewith and having an extension at the opposite end of said guiding frame reversely bent to form a work-holder in the path of said guide, a sliding carriage in said guide, a portable drill mounted on said carriage, a standard mounted on said portable drill, a lever-actuated segment gear mounted on said standard and meshing with rack, and arms secured at one end of the standard provided at the other with rollers engaging the rear faces of the frame to hold the gear and rack in meshed relation and guide the drill to and from the work.

HARRY H. EHLEN. 

